Telephone-transmitter.



PATENTED JULY 31, 1906. 0. 0. GILOHREST, TELEPHONE TRANSMITTER.APPLICATION FILED MAR.25,1905.

i'k nesse a x CHARLES C. GILOHREST, OF NEW YORK, N. Y.. ASSIGNOR TOWESTERN ELEOTBIO COMPANY, OF CHlCAGrO, ILLINOIS, A CORPORATION OFILLINOIS.

' no. senses.

Specification of Letters Patent.

TELEPHONE-TRANSMITTER.

- ratenteo. July 31, 1906.

' Application filed March 25. 1905. Serial No. 262,050.

To (all whom it may concern:

Be it known that 1, CHARLES C. GILonREsT, a citizen of the UnitedStates,'residing atNew York, in the county of New York and State of NewYork, have invented a certain new and useful Improvementin-Telephone-Transemitters, of which the following 1s a full, clear,concise, and exact description.

My invention relates to a telephone-transmitter of the tppe whereincarbon or other similar materi is interposed between a pair ofelectrodes adapted to be moved relativelyto one another to vary theresistance between them.

My object is to provide a telephone of this type which will be simpleand cheap to manufacture and whose working parts will'be easy toassemble, replace, and renew. With this aim in view I assemble thetransmitter-electrodes and their supporting parts asa unit and mountthem as a single part in a suitable frame.

I will describe my invention by reference to the accompanying drawings,wherein- Figure 1 is a longitudinal sectional view of a transmitterembodying my invention. Fig. 2 is a front view of the transmitter withthe case removed and a portion of thedampingring broken away to show thecontact-termi nal of the diaphragm. Fig. 3 is a front view of thetransmitter; and Fig. 4 is a view of the several parts ofthetransmitter, showing said parts in the relative positions in which theyare assembled.

The same letters of reference designate the same parts wherever they areshown.

The diaphragm a of the transmitter carries at its rear an electrode 6,preferably of carhen, which faces a similar electrode 0, mounted withina cup or dish d. The edge or rim of the cup at forms a fiat seat adaptedto support the diaphragm. Means are provide for preventingshOrt-oircuiting of the electrodes by said diaphragm and cup, said meanspreferably comprising an insulatingwasher 7, interposed between the rimof the cup and said diaphragm. A band of heavy elasticrubber e isprovided ion-binding or clamping together said cup and diaphragm andinterposed insulatingwasher, said band rtchcd over the edges of saidparts c assembled. This band serves ..s a iisniping-ring.

The electrode 12 may be mounted upon a suitable supporting-plate b,carrying a shank 6 which passes through the diaphragm a, a nut?) screwinupon the shank to bind the support I) in p ace. Similarly, the electrode0 may be provided with a supporting-plate c, carrying a shank c passingthrough the disk or cup (1, a nut 0 screwing upon the shank c to bindthe support 0 in place and serve as a terminal for said electrode.

The two electrodes b c are surrounded by a ring of felt h, and granulesof conducting material g, such as carbon, are laced between saidelectrodes 7) c in the cham er inclosed by said felt ring. I preferablyattach a washer i of non-elastic material to the ring h, fits tightlyupon the periphery of the supporting-plate c of electrode 0 to hold thering upon such the granules may be poured and held when the transmitter.is', being assembled. The ring it is flush with the diaphragm a, sothat a closed chamber is formed for the granules.

It will be noted that the air imprisoned or sealed between the diaphragmand cup, as well as the elastic ring it, serves as a dampener for thediaphragm, so that it is unnece ssary to employ a spring for thispurpose, as was done in transmitters of the prior art.

By virtue of the arrangement above described -that is, the mounting ofthe op posed electrodes rigidly upon the diaphragm o and the cup-shapedframe or dish d with an elastic ring surrounding'the edges of theelectrodes and inolosing the space between themit is possible toassemble the transmitter and obtain'maximum transmission by, merelybringing the above-mentioned parts together and holding them in positionmeans of the elastic damping-rm without requiring any adjusting of the eectrodes,

d since the diaphragm'in assembling the transmitter is not put under anyinitial tension, which would tend to impair the transmission.

The working circuit of the transmitter may, if desired, be readily keptinsulated from the frame by reason of the use of the rubber band, whichacts to clamp the working parts together and may serve electricallyinsulate the same from the frame. In the present embodiment of theinvention, however, the diaphragm a is provided with a terminal deviceconsisting of a plate It, lying electrode and form a cup in which.

also to which between the damping-ring and front surface I of thediaphragm in contact with the medam ing-ring in positionto contact withthe insi e of the metallic inclosing case. The

case thus forms one terminal of the transmitter and the bindin -post cand nut c the outer terminal thereo The working parts of my transmitterwhen assembled form a unit and ma be inserted in and removed from asuitab e fra'me'as a single part. '1 preferably insert the transmitterunit within a cup-shaped frame I, having a central opening Zv therein,into which a suitable mouthpiece m may pass, said mouthpiece beingscrewed into the plate over said opening. The said frame may be providedwith an inner annular shoulder n, against which the portion of thedamping-ring upon the diaphragm rests in order to insure free vibrationof the diaphragm.

A binding-ring 0 is adapted to be screwed within the frame until itrests against the portion of the damping-ring over the rim of the cup(Z, so holding the transmitter in proper position. .A suitable backplate or cover p may then be secured to the bindingring, preferably byscrews 1% p, as shown.

The transmitter above described, while efficient and substantial, isvery simple and cheap to manufacture. The parts require but littleskilled labor to produce or assemble. They are compact, easily fittedtogether, and when in place are readily accessible for purposes ofadjustment or repair.

1. In a telephone-transmitter, the combination with a diaphragn' of anelectrode carried thereby, a cup or dish supporting said diaphragm, butinsulated therefrom, a second electrode within said cup and securedthereto, cooperating with said first-mentioned electrode, and an elasticband fitting over the edges of said diaphragm and cup and binding thesame together.

2. .ln a telephone-transmitter, the combi nation with a diaphragm, of anelectrode carried thereby, a cup having a flat brim supporting the outeredge of said diaphragm, a second electrode within said cup and securedthereto facing said first-mentioned electrode, granules of conductingmaterial within said cup between said electrodes, means for pre ventingthe short-circuiting of said electrodes by said diaphragm and cup, andan elastic ring inclosing the outer edges of said cup and diaphragm tobind said parts together.

3.- In a telephone-transmitter, the combination with a diaphragm, of anelectrode carried thereby, a cup having an outwardly-projecting rim, asecond electrode within-the cup creases nation with-a diaphragm, of acarbon elec trode carried thereby, a cup having an out wardly-projectingrim, a second carbon electrode within said cup and secured theretofacing the first-mentioned electrode, a rub ber'damping-ring inclosingthe outer edge of said diaphragm and the rim to bind said partstogether, an insulating-washer between said diaphragm and rim, a feltring between the cup and diaphragm carrying a washer fitting tightlyupon one of said electrodes to form a cup, the other electrodeprojecting into the mouth of the cup, and carbon granules in said cupbetween said electrodes.

5. In a telephone-transmitter, the combination with a metal diaphragm,of an electrode carried thereby, a cup having an out wardly-p-rojectingrim, a second electrode within the cup, a supporting-plate therefor,

a shank carried thereby passing through said cup, a nut for the shankadapted to bind said plate in position and serve as a terminal for saidelectrode, a damping-ring inclosing the outer edges of the diaphra m andrim to bind said parts together, said iaphragm' and cup being insulatedfrom each other, granules of conducting material Within said cup betweensaid electrodes, a contact-plate between said damping-ring and diaphragmin contact with said diaphragm, and a lip or terminal piece connectedwith said plate and lying upon the outer surface of said damping-ring.

6. The combination with a telephonetransmitter comprising a diaphragm,an electrode carried thereby, a cup, an electrode carried therein facingsaid first-mentioned electrode, a damping-ring fo'r'binding saiddiaphragm and cup together, said parts being insulated from each other,and grapules of conducting material in said cup between said electrodes,of a containing-case for the transmitter having a central openingtherein, and a mouthpiece secured in said opening.

7. The combination with a telephonetransmitter, of a transmitter unit,an elastic clamping-ring therefor, a containing-case for said unit,comprising a cup-shaped frame within which the transmitter is carried,said frame having a central opening therein, a binding-ring adapted tobe screwed within the frame to lie a ainst the rear of the transmitterand lock the same in position, a back plate secured to said ring, and amouthpiece supported over the openingin the frame.

ICC

' ing insu reststo allow said diap 8. The combination with atelephonetransmitter comprising a diaphragm, an electrode carriedthereby, a cup, an electrode carried therein facing said first-mentionedelectrode,'a clamping-rmg for binding said diaphragm andcup together,said parts heated from each other, and armies of conducting materialin-said cup etween said electrodes, of a containing-case for-thetransmitter comprising a cup-shaped frame within which the transmitteris carried, an

annular shoulder in the inner surface of the front wall of the frameuponwhich the portion of the damping-rm upon the dia hragm hragm free viration,

a binding-ring adapted to screw within the frame against the portion ofthe dampingringupon said rim to lock the transmitter in osition, and aback plate secured to said inding-ring, said frame having a centralopening therein, and a mouthpiece secured to the frame over saidopening. 1

9. The combination with a telephonetransmitter unit comprisingadiaphragm, an electrode carried thereby, a cup supporting saiddiaphragm, an insulating-washer between said cup and diaphragm, a secondelectrode within said cu and secured thereto cooperating with saidst-mentioned-electrode,

astic clamping-ring for binding said.

and an e diaphragm and cup together, of a cup-shaped a to,

support, an insulatin on and binding said parts together, of a me ta liccontaining-case for said transmitter unit, and a contact pieee 7c lyingnext to the diaphragm inside the damping-ring and having a portion. is.adapted to make contact with the metallic case.

11. A transmitter unit co'mprising'a diaphragm, an electrode-carriedthereby, a cupshaped support for said diaphragm, an elastic ring forclamping said sup ort and diaphragm together, an electro 6 carried bysaid support facing said first-mentioned electrode, means for preventingshort-circuitin of said electrodesby said diaphra m and -ring surrouning the edges of said electro es to form a chamber,

a second ed to insulate and granules of conducting material within saidchamber between the electrodes; whereby the transmitter when assembledgives maximum transmission without requiringadjustment.

' 12. A transmitter unit comprising a diaphragm, an electrode carriedthereby, a cup shaped support for said diaphragm, an elastic ring forclamping saidsupport and diaphragm together, an electrode carried bysaid sup ort facing said first-mentioned electro e, means for preventingshortecircuiting of said electrodes by the diaphragm and its support, acushion-ring surrounding the edges of said electrodes'to form a chamber,said cushion-ring lying flush with the diaphragm, and forming, togetherwith the air, imprisoned between the support and diadampener for thediaphragm, and granules of conducting material within. said chamberbetween the electrodes,

13. In a transmitter the combination with .a diaphragm and a cup-shapedsupport therefor, of electrodes associated with said diaphragmandsupport, an elastic clamping- 118g adapted to clamp said diaphragm andsupport together to imprison a body of air between them, whereby saidimprisoned air constitutes a damper for the vibrations of saiddiaphragm.

. 14, In a transmitter the combination with an air-tight dia hragm andan air-tight dished support tnerefor, of electrodes associated therewithand adapted to be actuated by the vibrations of said diaphragm, anelastic ring embracing the peripheries of said diaphragm and support andsealing the same together to'form an air-tight chamber between them,whereby a body of air is confined to serve as a damping device for thevibrations of said diaphragm.

15. ,In a transmitter the combinationwith a transmitter-casing, of atransmitter unit comprising a diaphragm, aidisk-shaped support therefor,associated 'electrodesadapted to be actuated by the vibrations of saiddiaphragm, and an elastic ring clamping said diaphragmand supporttogether and adaptthe same from the casing, whereby the working parts ofthe transmitter are kept independent of theicasing and may be insertedin and removed from the casing as a unit.

In witness whereof I hereunto subscribe my name this 14th day ofFebruary, A. D. 1905.

' CHAS. G. GILCHREST; Y Witnesses:

FRANCIS L. GILM'AN, J. D. KENNEDY.

